Lightning-arrester.



N0- 838,304. PATENTED DEC. 11, 1906.

F. B. COOK. 1

LIGHTNING ARRESTER. APPLICATION FILED MAY 9, 1906.

UNITED STATES PATENT "oFFroE. FRANK B.- COK, OFCHIOAGO, ILLINOIS. LJG HTNING AFIRE STER.

Patented. Dec. 11, 1906.

Application filed May 9, 1906- vSerial Ho. 316'028- Y The principal objects of myinvention are to rovide a self-cleaning lightning-arrester an a lightning-arrester which will automatically short-circuit itself upon the continuance of an arc therethrough..

- In the lightning-arresters generally in usecomprising the usual carbon blocks and inter osed mica dielectric the mica holds the car ons apart during the continuance of anarcthrough the arrester, and .thereby allows -the carbons to becomered-hot and .the arc to continue until the carbon surfaces are actually burned together. Then, again, the mica dielectric provided with the usual holes therein provides a construction which holds carbon dustfor particles of carbon between the blocks, and thereby forms a shortecircuit throu h the arrester'when it is not desired.

Wit such an arrester the carbons have to be taken apartand cleaned after each ordinary discharge through' the arresten- In my present invention I preferably em ploy the usual carbon blocks for the electrodes of thearrester; but instead of the mica dielectric I employ a dielectric of a material which will become softened under -a continuedarc through the arrester, and thereby allow the carbon'blocks to be pressed together and short-circuited, thusstoppin the arc, Such a dielectric is very desirab em certain cases, especially in telephonesys tgrns exposed to electric light or street-car currents of reasonably high voltages. Then I cut away one side portion of the dielectric to near the center thereof, so as to allow the Per ticles of carbon which may be broken oii during a discharge through the arrester to fall from between the carbons, and thereby keep the air-space between the blocks free from obstructions and the lightning-arrester free from ably use a thin sheet of celluloid.

ashort-circuit after a discharge has passed therethrough.

Referring to the accompanying drawings,

Figure 1 is a perspective view of the li htningarrester of the invention, and Fig. 2 1s a side elevation of the dielectric of the invention.

The dielectric 2 is placed between the car- 'bon blocks 1 1, as shown in Fig. 1. One side portion of the dielectric 2 is cutaway, preferably as shown at 3.. This cut-away por-' tion fi allows the particles of carbon to fall from between the blocks 1 1 when the arrester shown in Fig. 1 is placed in a horizontal position. For this dielectric 2 are continues throu h the arrester for a short len th of time, the eat of the arc softens or me ts the celluloid dielectric 2, and thereby allows same to ooze out from between the blocks 1 1 due to the ordinary spring-pressure on the blocks 1 1, and the latter to make electrical connection with each other and estab- [ish a short-circuit therebetween, which stops the continuance of. the are. If the arc is of short duration, it will simply pass from one block to the other through the cutaway' portion 3 of the dielectric without melting or softening the latter. The lightning-arrester the circuit in any well-known manner.

Having thus described my invention, what I claim as new, and desire to secure byLetters Patent, is I 1. In a lightning-arrester of the character described, suitable electrodes held adjacent to each other,and a thin dielectric of softenable material interposed between the elec trodes and having one side ortion thereof cut away ap roximately to t e center.

2. In a hg tning-arrester of the character described, suitable electrodes held adjacent to each other, and a celluloid dielectric interposed between the electrodes and having a side portion thereof cut away approximately to the center.

Ivpreferen an shown in Fig. 1 may be held in place in 3. In a lightning-arrester of the character described, suitable electrodes held adjacent to each other, and a 'U-shaped celluloid dielectric inter osed between the electrodes.

4. In a lig tiling-arrester of the character described, suitable electrodes held adjacent to each other, and a U-shaped dielectric of softe'zmhle Irma-1'11 interposed between the As inventor of the foregoing I hereunto electrodes. subscribe my name, in the presence of two 10 In a Hg]!tUiIIQ-fliiiOStGl of the character subscribing Witnesses, this 7th day of May, described, rectangulm? carbon blocks suitably 1906 held in. a lmrizentel position and. adjacent to FRANK "B. COOK. each ether, and a ti-shaped (helectnc of heat- VV1tnesses: suscephhle nmte'z'ml interposed between the FREDERICK R. PARKER,

carbon blocks F. W. PARDEE. 

